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Reply-To: cem@freebsd.org
From: Conrad Meyer <cem@freebsd.org>
Date: Fri, 13 Sep 2019 11:55:49 -0700
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Subject: Re: Deadlock involving truss -f, pdfork() and wait4()
To: Mark Johnston <markj@freebsd.org>
Cc: Ryan Stone <rysto32@gmail.com>,
 FreeBSD Current <freebsd-current@freebsd.org>
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On Fri, Sep 13, 2019 at 11:37 AM Mark Johnston <markj@freebsd.org> wrote:
>
> On Fri, Sep 13, 2019 at 02:12:56PM -0400, Ryan Stone wrote:
> > This gets me a little further but now the wait4 call by the parent
> > never reaps the child and instead blocks forever:
>
> Does it perform a wildcarded wait(), or does it explicitly specify the
> PID of the child?  By design, the former will not return children
> created by pdfork().

Explicit PID:

https://people.freebsd.org/~rstone/pdfork.c

Best,
Conrad